1. Field of the Invention
The present invention relates to an information setting method and a wireless communication system.
Priority is claimed on Japanese Patent Application No. 2013-110252, filed May 24, 2013, the content of which is incorporated herein by reference.
2. Description of the Related Art
Recently, wireless communication systems have been implemented in plants, factories, or the like. In such a wireless communication system, site apparatuses (a measurement unit, an operation unit) called “wireless field apparatuses” which can perform wireless communication are provided in plants or the like, and control signals for controlling the wireless field apparatuses, measurement signals acquired by the wireless field apparatuses, and the like, are transmitted via a wireless communication network. The communication standard used for such a wireless communication system includes industrial wireless communication standards, such as ISA100.11a and WirelessHART (trademark).
For wireless devices such as the above wireless field apparatus to join the wireless communication network, it is necessary to set apparatus information (network parameters and security parameters) to the wireless device (this process is called “provisioning”). Provisioning methods include OTA (over the air) provisioning and OOB (out-of-band) provisioning. The OTA provisioning is a method such that provisioning is performed by wireless communication via the wireless communication network. On the other hand, the OOB provisioning is a method such that provisioning is performed by a communication means (such as infrared communication) different from wireless communication via the wireless communication network.
The wireless device having subjected to the provisioning transmits a join request (a request for joining the wireless network) to a management device of the wireless communication system at the time of joining the wireless network. The management device having received the join request performs an authentication process using information included in the join request (specifically, a join key). If the authentication succeeds, the management device allows the joining of the wireless device having transmitted the join request. If the authentication fails, the management device rejects the joining of the wireless device having transmitted the join request. Thus, a process of joining the wireless network is performed.
Shuji Yamamoto et al. “World's First Wireless Field Instruments Based on ISA100.11a”, Yokogawa Technical Report, Vol. 53, No. 2, 2010, discloses a provisioning device (apparatus parameter setting tool) that performs the aforementioned OOB provisioning on a wireless field apparatus caused to join a wireless network. Additionally, Japanese Patent Application Laid-Open Publication No. 2012-213125 discloses a provisioning device intended to enhance mutual connectivity with a wireless field apparatus.
The aforementioned OOB provisioning is classified into two methods. One method is a first provisioning method in which apparatus information (such as a join key) is generated and set by the same apparatus. The other method is a second provisioning method in which the apparatus information is generated and set by different apparatuses. Specifically, in the first provisioning method, the join key is generated and set by a provisioning device. On the other hand, in the second provisioning method, the join key is generated by a management device (manager) that manages a wireless network and is set by a provisioning device.
In a case where provisioning is performed by the first provisioning method, the provisioning device associates the set join key with an identifier of the wireless device (such as an EUI64 address), and the associated information is given and set to the manager. On the other hand, in a case where provisioning is performed by the second provisioning method, the identifier of the wireless device is given to the manager, the manager associates the join key with the identifier of the wireless device, and the associated information is set to the manager.
Here, various information, such as the aforementioned join key, is transmitted between the provisioning device and the wireless device by infrared communication or the like. On the other hand, various information is transferred between the provisioning device and the manager by use of a recording medium, such as an USB (universal serial bus) memory. For this reason, security is not ensured between the provisioning device and the wireless device, nor between the provisioning device and the manager.
Therefore, there is a possibility that the join key will be stolen by a malicious person. If the join key is stolen, the wireless network can be invaded, thereby causing security problems.
The present invention has been made in view of the above situations and has an object to provide an information setting method and a wireless communication system which can prevent information required for joining a wireless network from being stolen and thereby enhance the security.